| // SPDX-License-Identifier: BSD-2-Clause |
| /* LibTomCrypt, modular cryptographic library -- Tom St Denis |
| * |
| * LibTomCrypt is a library that provides various cryptographic |
| * algorithms in a highly modular and flexible manner. |
| * |
| * The library is free for all purposes without any express |
| * guarantee it works. |
| */ |
| #include "tomcrypt_private.h" |
| |
| /** |
| @file der_encode_bit_string.c |
| ASN.1 DER, encode a BIT STRING, Tom St Denis |
| */ |
| |
| |
| #ifdef LTC_DER |
| |
| /** |
| Store a BIT STRING |
| @param in The array of bits to store (one per char) |
| @param inlen The number of bits tostore |
| @param out [out] The destination for the DER encoded BIT STRING |
| @param outlen [in/out] The max size and resulting size of the DER BIT STRING |
| @return CRYPT_OK if successful |
| */ |
| int der_encode_bit_string(const unsigned char *in, unsigned long inlen, |
| unsigned char *out, unsigned long *outlen) |
| { |
| unsigned long len, x, y; |
| unsigned char buf; |
| int err; |
| |
| LTC_ARGCHK(in != NULL); |
| LTC_ARGCHK(out != NULL); |
| LTC_ARGCHK(outlen != NULL); |
| |
| /* avoid overflows */ |
| if ((err = der_length_bit_string(inlen, &len)) != CRYPT_OK) { |
| return err; |
| } |
| |
| if (len > *outlen) { |
| *outlen = len; |
| return CRYPT_BUFFER_OVERFLOW; |
| } |
| |
| /* store header (include bit padding count in length) */ |
| x = 0; |
| y = ((inlen + 7) >> 3) + 1; |
| |
| out[x++] = 0x03; |
| len = *outlen - x; |
| if ((err = der_encode_asn1_length(y, out + x, &len)) != CRYPT_OK) { |
| return err; |
| } |
| x += len; |
| |
| /* store number of zero padding bits */ |
| out[x++] = (unsigned char)((8 - inlen) & 7); |
| |
| /* store the bits in big endian format */ |
| for (y = buf = 0; y < inlen; y++) { |
| buf |= (in[y] ? 1 : 0) << (7 - (y & 7)); |
| if ((y & 7) == 7) { |
| out[x++] = buf; |
| buf = 0; |
| } |
| } |
| /* store last byte */ |
| if (inlen & 7) { |
| out[x++] = buf; |
| } |
| *outlen = x; |
| return CRYPT_OK; |
| } |
| |
| #endif |
| |
| /* ref: $Format:%D$ */ |
| /* git commit: $Format:%H$ */ |
| /* commit time: $Format:%ai$ */ |